The present invention relates to a hemostatic valve in a catheter introducer which is utilized for introducing e.g. an angiographic catheter into a sheath previously penetrated into a blood vessel in order to introduce the catheter into the blood vessel through the sheath.
The catheter introducer is provided with a hemostatic valve which enables removal and insertion of a catheter, and when the catheter is removed, this hemostatic valve should be closed to exhibit the hemostatic function.
Accordingly, a structure in which an open cut made in one side and another open cut in the other side are allowed to intersect partially or are connected to each other via a penetration hole is known as described in Japanese Patent Publication No. 949/1990.
A wide variety of patterns in the form of one letter, X shape, Y shape etc. are proposed for the cut described above, and any cut i.e. slit is closed like those made with a knife.
Because a slit such as that cut with a knife is strongly closed, the resistance of a catheter upon insertion into the slit is so great that the insertion involves pulling its surrounding portion into the slit, thus causing the operability of the catheter to worsen and resulting in great deformation of the outer periphery.
If the cut is formed as a narrow slit and pushed into a valve accommodating portion (valve room) to be given tightening force from the surrounding so as to permit the slit to be closed, not only operability is improved but the hemostatic function can also be satisfied.
In this case, however, too high a tightening force would cause an increase in the resistance of a catheter in passing through the slit to thereby decreasing it operability, whereas low tightening force would cause blood leakage. Even if the tightening force is suitable, the operability and hemostatic function would be affected adversely if the elasticity of the valve is changed due to a difference in frequency of use.
The present invention relates to a hemostatic valve for a catheter introducer for decreasing passage resistance by conferring the hemostatic function on the valve solely and minimizing tightening force, wherein a main body of the valve composed of plural layers is provided with at least one of a small penetration hole penetrating the center of each layer, a narrow slit having a crossing at the center and a cut having crossing at the center such that the small penetration hole or the narrow slit is allowed to be present in at least one layer, and a closed flap is provided at an opening in the boundary between the layer provided with the small penetration hole or the narrow slit and a layer adjacent to said layer.
A section of the small penetration hole is made circular, and the opening of said penetration hole is made to have a spherical face in contact with the boundary of a layer, or a section of the small penetration hole is made polygonal and the opening of said penetration hole is made to have a polygonal pyramid-shaped face having a tip in contact with the boundary of a layer, or a section of the opening of the narrow slit is made a curved face having a tip in contact with the boundary of a layer, or a section of the opening of the narrow slit is formed into a polygonal shape having a tip in contact with the boundary of a layer, whereby said flap can be formed.
The main body of the valve is provided on the face at the side for inserting a catheter, with a groove along the outer periphery.